Exhaust Gas Pressure Loss Calculation for Engine Control
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Solution Overview
Problem
Existing exhaust gas pressure loss calculation methods for engines with DPFs are inaccurate due to sensor response differences and delays, and fail to account for pressure loss variations in pipe parts, making precise control of EGR and fuel injection challenging.
Innovation Solution
A device that calculates corrected exhaust gas pressure loss by considering pressure loss across the DPF and adjacent pipe parts, using a typical sensor configuration to normalize pressure loss to a reference condition, allowing for precise control of EGR and fuel injection without adding new sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If DPF regeneration is triggered based on simple pressure loss threshold comparison, then control simplicity is maintained, but measurement precision deteriorates due to sensor response differences and pressure response delays
Solution Approach 1:
The system performs preliminary calculations to determine equivalent exhaust gas flow rates and equivalent pressure losses before comparing with thresholds. This pre-processing of data compensates for sensor response delays and establishes accurate baseline values for regeneration triggering, resolving the contradiction between simple control logic and precise measurement requirements
Solution Approach 2:
The invention introduces equivalent exhaust gas flow rate and equivalent pressure loss as intermediary parameters that mediate between raw sensor measurements and regeneration control decisions. These intermediaries normalize the data to account for sensor response characteristics, enabling both precise evaluation and simple threshold-based control
2Device complexity
If only DPF filter portion pressure loss is evaluated, then device complexity is reduced, but measurement precision deteriorates by excluding pipe part pressure losses
Solution Approach 1:
The exhaust system is segmented into distinct portions: pipe parts (upstream and downstream) and the DPF filter portion. Pressure losses are calculated separately for each segment using appropriate parameters, then combined to obtain the total equivalent pressure loss. This segmentation enables comprehensive evaluation without requiring complex integrated sensing
Solution Approach 2:
The evaluation system uses universal equivalent parameters (equivalent exhaust gas flow rate, equivalent pressure loss) that can represent both pipe part and filter portion characteristics. This multi-functional approach allows a single calculation framework to handle diverse pressure loss sources, maintaining simplicity while achieving comprehensive measurement
3Adaptability or versatility
If exhaust gas pressure loss control is adjusted for varying engine operating conditions, then adaptability is improved, but device complexity increases due to additional control parameters
Solution Approach 1:
The system adapts to varying engine operating conditions by dynamically adjusting key parameters: equivalent exhaust gas flow rate, equivalent pressure loss, and regeneration triggering thresholds. These parameter changes are based on real-time engine operating state detection, enabling the control system to maintain accuracy across different conditions without requiring complex additional hardware
Data Source
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AI summary
An object of the present invention is to provide a corrected exhaust gas pressure loss calculation device which corrects an exhaust gas pressure loss that varies from moment to moment in accordance with engine operating conditions to a corrected exhaust gas pressure loss that can be used directly in control. The present invention converts an exhaust gas pressure into the corrected exhaust gas pressure loss, which is an exhaust gas pressure loss under a reference condition, from a relationship between an exhaust gas mass flow rate and an exhaust gas mass flow rate under the reference condition, a relationship between an exhaust gas temperature and an exhaust gas temperature under the reference condition, a relationship between the exhaust gas pressure and an exhaust gas pressure under the reference condition, and a relationship between an exhaust gas viscosity coefficient under a condition of the exhaust gas temperature and a viscosity coefficient of a viscous gas under the reference condition.